The moon appears to be more complicated than we thought.

Up until a few years ago, everything related to the creation of the moon seemed pretty much settled.

In 1975, William Hart and Donald Davis put forth the giant impact hypothesis, whereby a glancing impact between the Earth and a planetesimal or larger object caused the Earth and the impact object to shed enough material to form a moon. Much of the hypothesis seemed to be confirmed by the Apollo moon rocks.

So, for more than 30 years, everything seemed settled.

But now, an article entitled "Impact Theory Gets Whacked" by Daniel Clery in the 11 October 2013 issue of Science reports that there are unsolvable flaws in the theory.

It seems that the isotopic composition of the moon rocks does not vary from the isotopic composition of rocks from the Earth, whereas all other rocks from space do vary noticeably. The giant impact hypothesis would require a large amount of the unearthlike material from the impact object to be present in the moon rocks. But it's not there.

This controversial information resulted in the first meeting in 15 years devoted to the formation of the moon at the Royal Society of London in September of 2013.

Several alternatives were suggested, but each alternative involved complicated side issues. The article quotes two of the participants: "We don't have a single scenario which stands out because of its simplicity," Canup said. Malosh agreed. "The solutions are contrived; they're not natural," he said. "We want a solution where isotopic similarity is a natural consequence of the model." 133pg183-185

Well, if they want isotopic similarity as a natural consequence of the model, then we can give it to them.

When I was first presenting my antipodal impact ideas to the Yahoo geology2 group, I proposed that simple impact extrusion would force material from the mantle to the surface at the antipode of a large impact. ChuckB disabused me of the notion that I could use simple impact extrusion of material from the mantle at the antipode of an impact for impacts that were the size of the Chicxulub impact object. The object would have to be much larger. ChuckB noted that impact extrusion is a near field phenomenon and that with much greater distances involved (in relation to the size of the impactor), the pressure and shear waves would be refracted in many directions.

However, in the case of the creation of the moon, we have no limitation on the size of the impact object. It can be as big as we need it to be in order to create a moon-sized object through the process of impact extrusion.


A few words of explanation about the impact extrusion process in modern industry would be appropriate here.

Used in the cold formed fastener business, the process of impact extrusion (also called trapped extrusion) involves the extrusion of metal at the other side of the impact, when using an impact header (see Illustration 7-A).

In the case of the impact header, the cold (room temperature, not heated) mild steel blank is trapped within a hardened steel die and then hit with a hardened steel punch, using great force. At the antipode of the impact, the steel blank's metal is forced to "flow" into the reduced diameter opening at the back of the die, resulting in a steel blank with an extruded section that has a smaller diameter (NOTE: In industry, this process is often used to create a shoulder bolt that has a shoulder diameter that is considerably larger in diameter than the smaller, extruded diameter, which is usually roll threaded [a process that creates screw threads] later. Using impact extrusion is a faster, less costly and less wasteful process than shaving the extra material away. Impact extrusion also provides better concentric tolerances, as well as keeping the steel grain structure intact).

The process of extreme antipodal uplift, in effect, would involve trapped extrusion. In the case of the impact header, the steel blank is trapped within a hardened steel die.

In the case of extreme antipodal uplift, the trapping is done by gravity (the weight of the rock of the lithosphere) and the shear strength of the rock of the lithosphere. The energy of the cosmic impact would, in effect, explosively extrude massive quantities of crust and mantle material at and near the antipode of the impact site, with the Earth's interior acting as an energy transfer mechanism.

Since the moon rock material would be extruded from the mantle, along with some material from the surface of the Earth, all of the moon rock would be rock from the Earth and none of the moon rock would be from the impact object.

To quote ChuckB.:

"the only way the opposite side of the Earth would display near field impulse phenomena, is if the bollide were on a planetary scale, enough to overwhelm the dispersive properties of the rock. This would necessarily throw ejecta into orbit to create a satellite and liquify a portion of the planet. The evidence, in the form of a single moon, suggests that this at most only happened once, and it was at a time when the mantle was already mostly liquid."
The article by Daniel Clery also states that there is difficulty in coming up with a theory where the moon would be a hot object in its early formation. Well, if the material is ejected from a partially molten mantle, that should solve that problem.

So it looks like I might get to use my original impact extrusion mechanism on a one-time-only basis after all. See Illustration 7 - A for a graphic depiction of the impact extrusion process.